Portable projection screen



, Feb 1945- J. L. STABLEFORD 2,395,3U%

PORTABLE PROJECTION SCREEN Filed April 12, 1945 Y Y 7 Inventor 91 Jon-LESLIESTABLEFORD d y Mg-751mb I Attorney Patented Feb. 19, 1946 mascotOFFICE PORTABLE PROJECTION SCREEN -iohn Leslie Stableford, London,England Application April 12, 1945, Serial No. 587,922

' In Great Britain April 21, 19 4 13 Claims.

This invention concerns improvements in portable projection screensparticularly intended for use in exhibiting cinematograph films, lanternslides and so on in halls, in the rooms of houses and other buildings,in ships and in like places having other main uses and only temporarilyemployed for these exhibitions, and the invention is more particularlyconcerned with collapsible projection screens of the kind where thescreen, when not in use, is housed in a box which forms a base-for theextended screen. One such form of collapsible portable screen isdescribed in the specification of my co-pending application No. 512,103,filed Nov. 29, 1943. This screen comprises a box in which thescreen ishoused when collapsed, the screen being rolled upon a spring roller towhich it is attached at one'end, this spring roller being mounted upon asupporting structure which, together with a rigid member attached to thefree end of the screen, constitutes the said box. The said rigid memberserves as a lath at the free end (iJe: the end remote from that attachedto spring roller) of the screen and is connected to the said rollersupporting structure by a pair of similar foldable or articulatedstrutsyeach formed by a pair of links hingedly connected together at oneend, one end of each articulated strut being pivotally connected to thesaid lath and the opposite end of each strut being pivotally connectedto the roller supporting structure.

In portable screens of this character it is highly desirable to make abox of the smallest possible dimensions to reduce its bulk and weight.The length of the box is more or less fixed by the width of the screenbut it is possible to construct a screen, in accordance with my patentapplication No. 512,103 for example, in which the front to back width ofthe'box is quite small and not very much in excess of the overalldiameter of the rolled up screen. However, when the box is made narrowin this way it is unstable when the screen is erected unless some formof stabilising means are provided, as for example the stabilising barsdescribed in the specification of my said patent application No.512,103. These stabilising bars are detachable and there is-consequentlya possibility that they may be lost; it is an object of this inventionto eliminate this possibility whilst a further object of the inventionis to provide an improved stabilising means whereby, inter alia. theefiort and time required to erect the screen for use may be furtherreduced. This invention therefore concerns, inter alia, improvements inor modifications of the invention claimed in the specification of mysaid application No, 512,103.

According to the invention there is provided a portable projectionscreen of the kind comprising a lone box in which the screen sheet ishoused when collapsed and from which it extends upwardly when in use,wherein the box is furnished between its ends with one or more pairs ofopenings, one opening of each pair being provided in the front wall ofthe box and the other in the rear wall of the box, and wherein one ormore stabilising members is or are provided which is or are movablerelatively to the box so as to be capable of being disposed in a screenstabilising position in which it projects or they project from withinthe box forwardly and rearwardly through the said openings and beyondthe box.

According to a further aspect of this invention the box adapted to housethe, collapsed screen and to form a base for the erected screen, isprovided with at least one stabilising member, this member beingattached to the box and disposed upon or adjacent the upper side of thebottom of the box in such a way as to be movable with respect to thesaid bottom either into an out-ofthe-way or stowed position in which itis wholly or mainly housed within the box, or into an operative positionin which a portion or portions of the stabilising member projects orproject transversely from the box through slot or opening means in thelongitudinal wall or walls of the box so as to increase the effectivewidth of the bottom of the latter.

The said stabilising member may comprise a rigid flat or mainly fiatelement (formed, for example, of wood or metal) centrally pivoted (e.g., by a bolt or rivet) to the upper side of the bottom of the box, suchelement being greater in length than in width, and the width of theelement being preferably equal to, or approximating to, the width of thebottom of the box so that when turned into its out-of-the-way positionthe element is wholl disposed within the external surface of the box,but when the element is turned into its operative position portions ofthe element extend through the slots or openings in the front and rearwalls of the box and forwardly. and rearwardly respectively beyond thesewalls.

Prefer-ably stop means are provided to limit the extent to which thestabilising member may be moved. Thus, when the stabilising member is inthe form of a centrally pivoted element as above described, an end ofone Or each of the slots in the front and rear walls of the box mayco-operate with an edge of the stabilising element ti) limit the anglethrough which it may move, preferably to approximately 90.

The slots in the front and rear walls of the box through which theprojecting ends of the stabilising member extend when the member is inuse are preferably such that the said Wall bear upon the upper surfaceof the stabilising member so as to relieve the pivot of the member of,or of most of, the strain borne by the stabilising member when thescreen is in use.

The ends of the stabilising member are provided with feet portionsadapted to engage the surface upon which the screen box is stood. Thesefeet would ordinarily be of a height equal to the thickness of the baseof the box, and they may be integral with or attached to the stabilisingmember or partially integral and partially attached. They may thus beformed wholly or partially as pads of a relatively soft material suchas, for example, rubber or felt. Recesses may be provided in the frontand rear edges of the bottom of the box to receive these feet when thestabilising member is in its out-of-the-way position.

Preferably the stabilising member has tWo straight parallel sides which,when the member is in the out-of-the-way position, are coincidentrespectively with the front and rear edges of the bottom of the box. Theend portions of the stabilising member may be rounded, or of triangularor any other suitable shape. Thus, for example. the stabilising membermay be, in plan, in the form of a strip equal in width to the bottom ofthe box and provided with rounded ends, or in the form of aparallelogram the width between the parallel sides of which is equal tothe width of the bottom of the box, or it may be of approximatelydiamond shape.

In order that the invention may be more readily understood certainembodiments of the same will now be described, by way of example only,as applied to a portable projection screen of the form described in thespecification of my patent application No. 512,103, such embodimentsbeing shown in the accompanying drawing, in which:

Figure 1 is a broken perspective view of a portable projection screen inthe open condition;

Figure 2 is a part section on line 11-11 Figure 1 and is drawn to alarger scale than Figure 1;

Figure 3 is a view similar to Figure 2 but shows the stabilising memberin its inoperative position;

Figure 4 is a section on line IVIV Figure 1, this figure also beingdrawn to a. larger scale than Figure 1;

Figure 5 is a view similar to Figure 2 and shows a modified form ofstabilising means; and

Figure 6 is a further view similar to Figure 2 and shows a still furthermodified form of stabilising means.

Referring to Figures 1 to 4 it will be seen that the portable projectionscreen there illustrated comprises a long rectangular wooden boxgenerally indicated by the reference I. Within the box is housed aspring roller 2 to which one end of a flexible rectangular sheet 3adapted to be wound on to the roller and having the end thereof,opposite to that attached to the roller 2, fixed to the underside of alath 4 also serving as the lid of the box I.

v The lath or lid 4 is connected to the back wall 5 of the box I by apair of articulated struts 6 and I, the lower links 8 and 9 of which arepivoted, at a distance from their lower ends, to the upper part of thesaid rear wall 5. The lower extremity of each of said lower links 8 and9 is connected by a spring, such as that marked II) in Figure 4, to abracket II on the rear wall 5 of the box. A screen such as so fardescribed is in accordance with my hereinbefore mentioned patentapplication No. 512,103.

In applying this invention to the screen at least one stabilising memberI I is provided. This member is formed from a piece of wooden strip ofthe same width as the bottom I3 of the box and having its end portionsout obliquely so that the stabilising member is of parallelogram shapein plan. The stabilising member so formed is laid flat upon the upperside of the bottom I3 of the box and a bolt or rivet I4 is passedthrough the stabilising member at the intersection of its diagonals andthrough the bottom of the box on the longitudinal centre-line thereof toconstitute a vertical pivot about which the stabilising member may turnin a plane parallel to the upper surface of the bottom of the box. Iftwo or more stabilising members are employed instead of only one, thenthe stabilisers are longitudinally spaced along the bottom of the box.

For the, or each, stabilising member I2 the front wall I5 and the rearwall 5 of the box are provided respectively with longitudinal openingsor slots I6 and I1 adjacent the bottom I3 of the box, these slotsextending transversely through the said walls and being of approximatelythe same-length as, and relatively longitudinally offset to the samedegree as, the longitudinal parallel sides I8 and I9 of the stabilisingmember.

At least one end of. each of the slots I6 and I1 is cut obliquely at 20so as to lie along and engage as stop means the oblique end edges 2I and22 of the stabilising member when this is in the inoperative positionshown in Figure 3. The ends 20 of the slots I6 and I! also engage theedges I8 and IQ of the stabilising member I2 when in its operativeposition (as shown in Figure 2) to limit the opening movement of themember. The said slots are approximately equal in depth to the thicknessof the stabilising member.

At each of its diagonally opposite acute angled corners, and on itsunderside, the stabilising member is provided with a foot 23 equal inheight to the thickness of the bottom I3 of the box, which bottom isprovided at its front and rear edges with recesses 24 to house the saidfeet when the stabilising member is in its out-of-the-way position.These recesses are preferably sufiiciently large, or have their edgechamfered off on the underside at 25, to enable a finger to be insertedbehind the foot of the stabilising member to facilitate the pulling outof the said member from the inoperative to the operative position.

When the stabilising member is extended to its operative position asshown in Figures 1, 2 and 4, the feet 23 rest upon the surface uponwhich the box I is placed and so form a forward and rearward extensionof the base of the box and serve to stabilise it against tilting overbackwardly or forwardly. Furthermore any strain to which the stabilisingmember may be subjected in performing its work is taken by the front andrear walls of the box and not the bolt I4 since the said walls bear uponthe upper side of the stabilising member. When not in use thestabilising member is housed entirely within the compass of the'box I asclearly shown in Figure 3.

If desired, instead of making the stabilising member in one piece asabove described, it may, as shown in Figure 5, be made in two parts 26and 2'! halved together at their inner ends and hinged on a common pivot28 within the box and each adapted to be swung out of the box th'roughthe corresponding slot 29 or 30 in the longitudinal rear or front wallof the box into the projecting operative position. If desired the twoparts and 21 may be carried by separate pivots.

Alternatively, as shown in Figure 6, a stabilising member made in twoparts 3| and 32 may have these parts arranged to slide endwise into andout of the box transversely to the length of the latter, the lengths ofthe parts of'the stabilising member being transverse to the length ofthe box, and the said parts being guided in penings 33 and 34 in thefront and rear walls of the box and also in brackets 35. To limititsoutward movement each part 33 and 34 may have a stop plate or part 31at it inner end to engagethe bracket 35.

It will be understood that according to the above described embodimentsof the invention the stabilising means are unitary with the box, thatwhen not in use they are completely disposed within the outer dimensionsof the box; when in use they are firmly supported between the bottom andthe front and rear walls of the box; the stabilising means may bequickly and easily moved into or out of operation; and that when thetabilising means are in the inoperative position the openings throughwhich they pass when in use, are closed.

What I claim is:

1. A portable projection screen comprising a box, a screen sheet adaptedto be extended upwardly from said box for use and to be housed in thebox when not in use, said box having at least one pair of openingsbetween its ends, one such openingv of each pair being provided in thefront wall and the other in the rear wall of the box, and a stabilisinmember for each pair of said openings, said stabilising member beingmovable relatively to the box for disposal alternatively in a stowedposition and in an operative position wherein it projects from withinthe box forwardly and rearwardly through the said openings in the frontand rear walls of the box, and beyond the box.

2. A portable projection screen comprising a long box, opening means inthe perimeter of said box, a screen sheet adapted to be extendedupwardly from the box for use and to be housed in the box when not inuse, and at least one stabilising member disposed above and adjacent thebottom of the box, said stabilising member being movably attached to thebox and adapted for disposal in a stowed position within the compass ofthe box and alternatively in an operative position in which it projectsfrom within the box through said opening means and outwardly beyond thebox transversely of the length thereof.

3. A portable projection screen comprising a long box, opening means inthe perimeter of said box, a screen sheet adapted to be extended for useupwardly from the box and to be housed in the box when not in use, andat least one stabilising member disposed above and adjacent the bottomof the box, said stabilising member being pivoted to the box within thelatter and adapted for disposal in a stowed position within the compassof the box and alternatively in an operative position in which itprojects from within the box through said opening means and outwardlybeyond the box transversely of the length thereof.

4-. A portable projection screen comprising a box, opening means in theperimeter of said box, a screen sheet adapted to be extended for useupwardly from the box and to be housed in the box when not in use, andat least one stabilising member disposed above and adjacent the bottomof the box, said stabilising member being longer than the width of thebox from front to back and being pivoted between its ends to the bottomof the box and adapted for disposal in a stowed position within thecompass of the box and alternatively in an operative position in whichit projects from within the box through said opening means and outwardlybeyond the box transversely of the length thereof.

5. A portable projection screen comprising a long box, longitudinalslots being provided respectively in the front and rear walls of saidbox, a screen sheet adapted to be extended for use upwardly from the boxand to be housed in the box when not in use, and at least onestabilising member disposed above and adjacent the bottom of the box,said stabilising member being a flat element of a length greater thanthe width of the box from front to back and being pivoted midway betweenits ends to the upper side of the bottom of the box on the longitudinalc'entre line of such bottom, and said stabilising member being adaptedto be swung through a right angle from a stowed position within thecompass of the box to a position in which it projects transversely fromthe box through said longitudinal slots.

6. A portable projection screen according to claim 5, wherein the saidstabilising member has a dependent foot at each end and the box isrecessed to receive these feet when thestabilising member is stowed.

7. A portable projection screen comprising a long box, recesses beingprovided in the front and rear walls and bottom of said box, a screensheet adapted to be extended for use upwardly from the box and to behoused in the box when not in use, and at least one stabilising memberdisposed above and adjacent the bottom of the box, said stabilisingmember being a flat element of a width equal to and of a length greaterthan the width of the box from front to back and being pivoted midwaybetween its ends to the upper side of the bottom of the box on thelongitudinal centre line of such bottom, and said stabilising memberbeing adapted to be swung through substantially a right angle from astowed position within the compass of the box to a, position in which itprojects transversely from the box through longitudinal slots providedrespectively in the front and rear walls of the box, and a dependentfoot at each end of said stabilising member, such feet being adapted tobe received, when the stabilising member is stowed, in said recesses.

8. A portable projection screen comprising a long box, recesses beingprovided in the bottom of said box, a screen sheet adapted to beextended for use upwardly from the box and to I be housed in the boxwhen not in use, and at least one stabilising member disposed above andadjacent the bottom of the box, said stabilising member being a flatparallelogram-shaped element of a width equal to, and of a lengthgreater than, the width of the box from front to back and being pivotedmidway between its ends to the upper side of the bottom of the box onthe longitudinal centre line of such bottom, and said stabilising memberbeing adapted to be swung through substantially a right angle from astowed position within the compass of the box to a position in which itprojects transversely from the box through longitudinal slots providedrespectively in the front and rear walls of the box, and a dependentfoot at each end of said stabilising member, such feet being adapted tobe received, when the stabilising member is stowed, in said recesses.

9; A portable projection screen according to claim 8, wherein the saidlongitudinal slots in the front and rear walls of the box are equal inlength to the longitudinal parallel edges of said stabiliser and arerelatively offset to the same extent as these edges.

10. A portable projection screen comprising a long. box, opening meansin the perimeter of said box, a screen sheet adapted to be extended foruse upwardly from the box and to be housed in the box when not in use,and at least one stabilising member disposed above and adjacent thebottom of the box, such stabilising member being anchored. to thebox forguided sliding movement in a direction transversely of the length of thebox and being adapted for disposal in a stowed position within thecompass of the box and a1- ternatively in an operative position in whichit projects from within the box throughsaid openmg means and outwardlybeyond the box transversely of the length thereof.

11. A portable projection screen according to claim 10, having at leasta pair of said slidable stabilising members, one adapted to be projectedthrough the front wall and the other through the rear wall of the box.

12. A portable projection screen comprising a long box, opening means inthe perimeter of said box, a screen sheet adapted to be extended for useupwardly from the box and to be housed inthe box when not in use, and,at least one pair of stabilising members, each of these members beingpivoted to the bottom of the box within the latter and each beingadapted for disposal in a stowed position within the compass of the boxand alternatively in an operative position in which it projects fromwithin the box through said opening means and outwardly beyond the boxtransversely of the length thereof, and the two stabilising members ofthe pair being adapted, in their operative positions, to project inopposite directions from the box.

13. A portable projection screen according to claim 12;, wherein thestabilising members of the pair are pivoted upon a common pivot.

JOHN LESLIE STABLEFORD.

